A hernia is the protrusion of part of a body pan or structure through a defect in the wall of a surrounding structure. Most commonly, a hernia is the protrusion of part of abdominal contents, including bowel, through a tear or weakness in the abdominal wall, or through the inguinal canal into the scrotum.
An abdominal hernia is repaired by suturing or stapling a mesh patch over the site of the tear or weakness. The mesh patch has a rough surface that can irritate the bowel and cause adhesions. It is therefore preferred to install the patch properitoneally. The mesh patch is preferably attached to the properitoneal fascia of the abdominal wall, and covered by the peritoneum. To attach the mesh patch to the properitoneal fascia, the peritoneum must be dissected from the properitoneal fascia. This is a difficult process. There is a risk of puncturing the peritoneum. Moreover, strands of properitoneal fat interconnecting the peritoneum and the properitoneal fascia make it difficult to see the site of the hernia.
The use of laparoscopic techniques to perform hernia repair is becoming increasingly common. In the conventional procedure for carrying out a hernia repair laparoscopically, an endoscope and instruments are introduced into the belly through one or more incisions in the abdominal wall, and are advanced through the belly to the site of the hernia. Then, working from inside the belly, a long incision is made in the peritoneum covering the site of the hernia. Part of the peritoneum is dissected from the properitoneal fat layer to provide access to the fat layer. This is conventionally done by blunt dissection, such as by sweeping a rigid probe under the peritoneum. In this procedure, it is difficult to dissect the peritoneum cleanly since patchy layers of properitoneal fat tend to adhere to the peritoneum.
In an alternative known laparoscopic hernia repair procedure, the belly is insufflated. An incision is made in the abdominal wall close to the site of the hernia. The incision is made through the abdominal wall as far as the properitoneal fat layer. The peritoneum is then blunt dissected from the properitoneal fat layer by passing a finger or a rigid probe through the incision and sweeping the finger or rigid probe under the peritoneum. After the peritoneum is dissected from the properitoneal fat layer, the space between the peritoneum and the properitoneal fat layer is insufflated to provide a working space in which to apply the mesh patch to the properitoneal fascia. During the blunt dissection process, it is easy to puncture through the peritoneum, which is quite thin. A puncture destroys the ability of the space between the peritoneum and the fascia to hold gas insufflation. Also, it is difficult to dissect the peritoneum cleanly since patchy layers of properitoneal fat tend to adhere to the peritoneum.
U.S. patent application Ser. No. 794,590, of which application this application is a Continuation-in-Part, discloses a laparoscopic hernia repair technique that enables a mesh patch to be attached to the properitoneal fascia without breaching the peritoneum. An incision is made through the abdominal wall as far as the properitoneal fat layer. A multi-chambered inflatable retraction device is pushed through the incision into contact with the peritoneum, and is used to separate the peritoneum from the underlying layers. The main end chamber of the inflatable retraction device is then inflated to elongate the inflatable retraction device towards the site of the hernia. As it inflates, the inflatable retraction device gently separates the peritoneum from the underlying layers. Once the main chamber of the inflatable retraction device is fully inflated, a second inflatable chamber is inflated. The second inflatable chamber enables the inflatable retraction device continue to separate the peritoneum from the underlying layers after the main inflatable chamber has been deflated.
One or more apertures are then cut in the envelope of the main inflatable chamber to provide access to the site of the hernia for instruments passed into the main chamber. With such an arrangement, instruments pass through the main chamber situated between the peritoneum and the underlying layers. In this way, a gauze patch can be attached to the properitoneal fascia without breaching the peritoneum.